The invention relates to conveyor belt systems and in particular to a tool for removing the worn lagging strips on a conveyor belt drum.
A common problem in conveyor belt systems where the belt is used to transport heavy materials, for example coal, is slippage of the conveyor belt on the pulley drums which drive the belt. A recent development has been the use on the drums of what are referred to "lagging strips". Lagging strips are long, rectangular, rubber strips which are secured to the circumference of the drum parallel to the axis of rotation. They have a thick central rubber portion which contacts the conveyor belt, and a thin border strip which secures the lagging strip to the drum by means of metal strips which are welded to the drum and are provided with clips to secure the edges of the lagging strips. This configuration has been found to give much better friction between the drum and the conveyor belt than would a continuous coating of rubber on the drum. The strips are typically 55/8 inches wide and 11/16 inches thick.
As the lagging strips become worn it is necessary to replace them. This has been a difficult task as the metal clips become rusted and the lagging strips fused to the surface of the pulley. In the past, the method of removing the lagging has been to utilize a torch to loosen the lagging, use a hammer and chisel to loosen the metal clips from the lagging strips, and then use a tool such as a "come-along", hammers and chisels and torches to strip and remove the lagging from the pulley. This is a difficult and time consuming procedure. In the past up to four hours have been necessary to remove a single lagging strip, and it is also then difficult to install a new lagging strip as the metal clips have been bent out of shape and damaged. Further, in order to carry out this procedure it is necessary to shut the machine down, remove the pulley from the machine and transport it to a shop where the various tools are available. This results in the machine being out of commission for an extended period of time, resulting in substantial economic loss, unless the facility maintains replacement drive pulleys. As a typical drive pulley has about twelve lagging strips, it is apparent that the previous method was extremely time consuming.
The present invention provides a tool for quickly and effectively removing lagging strips from drive pulley drums. The present invention also leaves the metal clip in a condition after removal of the lagging strip such that the replacement strip may be easily installed. The present invention may be mounted directly on the pulley drum while the drum is still in place in the machine and accordingly it is not necessary to remove and transport the pulley drum. In contrast to prior methods, the present method allows the lagging strips from an entire drum to be removed much more quickly. Further, the procedure leaves the metal clips in a condition whereby the replacement lagging strip can be easily installed.